In order to assess the relationship of infection with the human papillomaviruses (HPV) to risk of subsequent cervical neoplasia, a follow- up study of 10,000 women with no evidence of cytologic abnormalities will be conducted. This study will be conducted in a region of costa Rica that has an incidence rate of cervical cancer approximately 6 times higher than that observed in the United States. At the beginning of this 5-year project, a random sample of the female population within the study region will be identified and recruited for study participation. From each woman, a Pap smear, cervical specimen, blood specimen and personal interview will be obtained. This will allow an examination of risk factors related to prevalent cervical disease. Subsequently, these women will be followed passively through matching identification numbers of subjects against the costa Rican national cytology and cancer registries. A subcohort of about 3,200 women will be followed actively. Women with incident or progressive cervical abnormalities will be identified and matched with non-cases for subsequent case-control analyses. These analyses will enable the assessment of risk in relation to infection with HPV and other agents, allowing further definition of the natural history of cervical abnormalities. In addition, collected data will enable identification of those factors associated with the progression of low- grade abnormalities to higher grade disease.